<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
 <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <title>Flot Examples</title>
    <link href="layout.css" rel="stylesheet" type="text/css">
    <!--[if lte IE 8]><script language="javascript" type="text/javascript" src="../excanvas.min.js"></script><![endif]-->
    <script language="javascript" type="text/javascript" src="../jquery.js"></script>
    <script language="javascript" type="text/javascript" src="../jquery.flot.js"></script>
    <script language="javascript" type="text/javascript" src="../jquery.flot.crosshair.js"></script>
 </head>
    <body>
    <h1>Flot Examples</h1>

    <div id="placeholder" style="width:600px;height:300px"></div>

    <p>You can add crosshairs that'll track the mouse position, either
    on both axes or as here on only one.</p>

    <p>If you combine it with listening on hover events, you can use
    it to track the intersection on the curves by interpolating
    the data points (look at the legend).</p>

    <p id="hoverdata"></p>

<script type="text/javascript">
var plot;
$(function () {
    var sin = [], cos = [];
    for (var i = 0; i < 14; i += 0.1) {
        sin.push([i, Math.sin(i)]);
        cos.push([i, Math.cos(i)]);
    }

    plot = $.plot($("#placeholder"),
                      [ { data: sin, label: "sin(x) = -0.00"},
                        { data: cos, label: "cos(x) = -0.00" } ], {
                            series: {
                                lines: { show: true }
                            },
                            crosshair: { mode: "x" },
                            grid: { hoverable: true, autoHighlight: false },
                            yaxis: { min: -1.2, max: 1.2 }
                        });
    var legends = $("#placeholder .legendLabel");
    legends.each(function () {
        // fix the widths so they don't jump around
        $(this).css('width', $(this).width());
    });

    var updateLegendTimeout = null;
    var latestPosition = null;
    
    function updateLegend() {
        updateLegendTimeout = null;
        
        var pos = latestPosition;
        
        var axes = plot.getAxes();
        if (pos.x < axes.xaxis.min || pos.x > axes.xaxis.max ||
            pos.y < axes.yaxis.min || pos.y > axes.yaxis.max)
            return;

        var i, j, dataset = plot.getData();
        for (i = 0; i < dataset.length; ++i) {
            var series = dataset[i];

            // find the nearest points, x-wise
            for (j = 0; j < series.data.length; ++j)
                if (series.data[j][0] > pos.x)
                    break;
            
            // now interpolate
            var y, p1 = series.data[j - 1], p2 = series.data[j];
            if (p1 == null)
                y = p2[1];
            else if (p2 == null)
                y = p1[1];
            else
                y = p1[1] + (p2[1] - p1[1]) * (pos.x - p1[0]) / (p2[0] - p1[0]);

            legends.eq(i).text(series.label.replace(/=.*/, "= " + y.toFixed(2)));
        }
    }
    
    $("#placeholder").bind("plothover",  function (event, pos, item) {
        latestPosition = pos;
        if (!updateLegendTimeout)
            updateLegendTimeout = setTimeout(updateLegend, 50);
    });
});
</script>

 </body>
</html>
